Program in Ecology’s

Ecology Student Symposium February 22, 2013

Berry Biodiversity Conservation Center

Oral and Poster Presentations Abstract Book

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12:00 Opening Remarks, Dr. Andy Hansen, Academic Affairs 12:15 KEYNOTE ADDRESS – Berry Center 138

Predicting the effects of climate change on biodiversity: Different approaches for different scales

Dr. Chris Funk, Colorado State University

ORAL PRESENTATIONS SESSION - Berry Center 138 1:30pm Genomic analysis of sucker hybridization Liz Mandeville, Tom Parchman, David McDonald, C. Alex Buerkle Non-native white suckers are known to hybridize with native flannelmouth and bluehead suckers throughout the Upper Colorado River basin. We used genomic approaches to understand how genetic outcomes of hybridization vary by river drainage and hybridizing species pair. We generated DNA sequence data for 1400 individual suckers from Wyoming, Colorado, and Utah, and identified 2,787 variable nucleotides. We used these data to gain a fine-scale understanding of genetic variation within and among species, and to compare hybridization among drainages. We found that outcomes of hybridization vary substantially, both by river drainage and by hybridizing species pair. Our data suggest that hybrids range from F1 hybrids to extremely backcrossed individuals (which are likely indistinguishable morphologically from parental species). Additionally, direction of backcrossing and extent of introgression appear to vary by river drainage. For all drainages, extensive introgression is more common in flannelmouth x white sucker crosses than in bluehead x white sucker crosses. This variability will lead to improved understanding of the genetic architecture of reproductive isolation. Additionally, these results may improve sucker management by enabling biologists to integrate knowledge of the local genetic context for hybridization with the range of sucker phenotypes observed in the field. 1:45pm Evaluation of the reintroduction of Attwater’s prairie-chickens using pen-rearing birds Aaron Pratt, Mike Morrow, John Toepfer The reintroduction of endangered Attwater’s prairie-chickens (APC, Tympanuchus cupido attwateri) raised in captive-breeding facilities has prevented extinction but only maintained the population at low levels. Releases were initiated in 1996 at the Attwater Prairie Chicken National Wildlife Refuge and the Texas City Prairie Preserve. During 2007, the first private-lands release was commenced in Goliad County, Texas. Survival and reproduction of released pen-reared birds will determine the success of these reintroductions, and ultimately the species recovery. We evaluated the reintroduction of APCs using pen-reared birds by comparing post-release survival and brood survival among the 3 release sites and a reference population of wild greater prairie-chickens (GPC, T.c. pinnatus) in Minnesota. All 3 release sites had lower survival than past estimates for wild APCs and contemporary GPCs. Likewise, brood survival at all release sites was significantly lower than wild birds. Both post-release survival and brood survival are contributing limiting factors in the successful reintroduction of

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APCs. Therefore, we developed a population model and used RAMAS Metapop to simulate an APC population through a recovery period. We determined the threshold needed for successful recovery and the sensitivity of model predictions for 3 variables: number of birds released, post-release survival, and brood survival. Brood survival was the only variable that could be increased independently and have a successful recovery. Releasing more birds with higher survival will help recover the APC faster but a successful recovery will not be possible without improved brood survival. 2:00pm Effects of human development and site productivity on the landscape genetics of

Southern Idaho ground squirrels Adi Barocas, Victoria H. Zero, Agnès Pelletier, Daryl Trumbo, Jessica Castillo, Xavier Giroux-Bougard, Denim Jochimsen, Mark Linell, Rachel Pigg, Kristen Lohr, Diane Evans-Mack, Stephen Spear, Melanie Murphy, Lisette P. Waits

The Southern Idaho Ground Squirrel (Urocitellus brunneus endemicus; SIDGS) is a ground-dwelling rodent which inhabits a limited geographic range within the central area of Idaho. Remaining populations of SIDGS are of increasing conservation concern due to significant fragmentation of their habitat, resulting from agricultural activity. Previous genetic analyses indicate limited functional connectivity among sparsely distributed populations of SIDGS. However, the landscape-related factors that limit SIDGS movement are poorly understood. We used gravity modeling, a network-based approach which incorporates the effects of both the productivity of habitat patches sampled and landscape resistance among sampling locations, to test multiple hypotheses on the factors that limit gene flow. Genetic data was obtained from 312 individuals in 11 known localities. We found that SIDGS connectivity was negatively correlated with geographic distance between sites. In addition, site productivity variables had mostly positive effects on gene flow. Interestingly, between-site variables reflecting human activity and small-scale topography appeared to promote gene flow. Our model results suggest combined effects of climate-driven site productivity, human development and topography determining SIDGS connectivity. The gravity modeling approach provides a multivariate framework to elucidate SIDGS vulnerability to habitat fragmentation and has implications for conservation and management decisions. 2:15pm Snow distribution and soil respiration in sagebrush steppe Colin Tucker, Kiona Ogle, Elise Pendall Soil respiration is one of the largest fluxes in the terrestrial carbon cycle and is critical in determining the concentration of CO2 in the atmosphere. Soil respiration is the cumulative result of all aerobic biotic activity in the soil, and as such, is controlled by a wide range of physical and biological factors. Understanding how soil respiration responds to changes in these factors is necessary to make accurate predictions of future atmospheric CO2 and therefore climate change. In this study, we focused on soil respiration in sagebrush steppe ecosystems in Wyoming. Sagebrush steppe is both geographically extensive and relatively understudied in terms of the global carbon cycle, making this an important study. We focused on role of snowpack, temperature and vegetation in determining soil respiration, and the seasonal variation in soil respiration. We used highway

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snowfences as an artificial snow manipulation experiment. Because our goal is to generate a quantitative, predictive understanding of soil respiration, we additionally compared a range of models of soil respiration to determine which model was best able to replicate observation of soil respiration. We found that the role of winter snowpack in regulating soil liquid water content was a critical determinant of soil respiration in winter and early in the growing season, but for different reasons. A deep snowpack insulates the soil mid-winter, preventing or reducing soil freezing, resulting in significantly higher soil respiration rates under deeper snow. Winter snowfall, not growing season rain, is the dominant water source in sagebrush steppe. We found that in the early growing season, after snowmelt, the positive effect of elevated snowpack on soil respiration persisted due to increased soil moisture. This effect diminished into the summer, possibly because the snowpack in 2012 was lower than normal, and the growing season was very dry, such that all locations were dry by the mid-summer sampling. Thus, we conclude that winter snow is a critical driver of soil respiration during the winter and growing season in sagebrush steppe. 2:45pm Population genetic structure in natural populations of hybridizing spruce species in

the central Rocky Mountains Monia Haselhorst, C. Alex Buerkle Areas of geographic overlap between hybridizing species provide the opportunity to study interspecific gene flow and the nature of species boundaries. We recently completed a study of population genetic structure in natural populations of Picea glauca (white spruce) and P. engelmannii (Engelmann spruce) in the central Rocky Mountains of North America, a geographic region where hybrids and isolation between species had not previously been studied. We identified hybrids by their genetic composition at 17 microsatellite markers, and determined the broad-scale geographic distribution of hybrids in this region. We found considerable variation in ancestry within and among collection sites, suggesting that within this area of geographic overlap, the interaction of the two species varies extensively. The results document a previously unrecognized patchy distribution of hybrids between Engelmann and white spruce, including locations where hybrids were not known or expected to exist. Further, the ancestry of many hybrids was consistent with multiple generations of hybridization, suggesting a relatively porous species boundary. The identification and characterization of hybridization between these spruce in this region raises the question of what factors maintain species boundaries in these long-lived forest trees. By providing novel distributional information and characterization of genetic variation in hybrids and parental species, we laid the groundwork for further studies of the genetic basis of barriers to gene flow and predictions on how hybridization could influence the response of spruce to future environmental fluctuations. 3:00pm Can elk mitigate disturbance risk associated with natural gas development? Clay B. Buchanan, Jeffrey L. Beck Ungulates must balance resource selection and acquisition of forage of variable quality/quantity with the risks of human disturbance. Our study was based in the 500-km2 Fortification Creek Area (FCA) of northeastern Wyoming, USA, where over 700 coal bed natural gas (CBNG) wells have been developed since 2000. Our

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research in the FCA indicates that elk (Cervus elaphus) avoidance of roads has led to a reduction in the use of high quality habitat of approximately 30%. In this study, we focus on elk response to disturbance risk associated with CBNG development, including fine-scale temporal (day and night) resource selection decisions relative to forage availability. We used environmental and anthropogenic infrastructure data to develop multiple regression models to identify temporal elk resource selection shifts during summer and winter from 2008 to 2010. We assessed the relationship between forage availability and observed selection shifts to quantify the ability of elk to mitigate disturbance influences through daily movement patterns. Our results suggest elk shifted daily resource selection patterns in response to differences in forage quality and quantity between seasons. However, these patterns were not consistent enough to support the hypothesis that elk can mitigate disturbance risk through daily selection shifts. During our study there was greater than average precipitation, which likely influenced forage production, thus patterns of resource selection may be more defined during normal precipitation years. Because, elk may not be capable of mitigating disturbance risk through daily resource selection shifts, management priority should be to reduce human activities associated with energy development. 3:15pm Does publication bias create misleading estimates of climate-induced range shifts?

Daniel Gibson-Reinemer, Frank Rahel Publication bias in scientific literature can result from well-intended aspects of publishing, including the preference for significant results. When meta-analyses estimate the magnitude of a particular process, the presence of publication bias can skew the data substantially. One area in ecology that may be particularly vulnerable to publication bias is studies of how species’ ranges are shifting in response to climate change. Two meta-analyses have attempted to estimate the rate at which species are moving poleward or uphill with rising temperatures, and the results of these analyses are influential in conservation planning and policymaking. However, a bias toward reporting large effects may exaggerate the impact of climate change on species’ range shifts. Here, we analyze studies documenting climate-induced range shifts to examine the extent to which global estimates of species’ range shifts are impacted by biases in scientific publishing. 3:30pm Can one science class make a difference? Getting non-science majors comfortable with

science David E. Reed, Mark E. Lyford Science education for non-science majors presents many challenges to college educators due in part to the social and political context and implications. This presents multiple barriers to learning for the student, both because of the inherit science literacy issues, and because many students have strong preconceived feelings or beliefs about science. A further barrier to learning for non-science majors is that very often the number of required science courses is low and highly complex issues such as climate change is difficult to address in introductory science courses. To attempt to address these issues a course for non-science majors, Life Science 1002, Discovering Science, was created as an interdisciplinary and integrated science. Our previous work has shown a clear change in the reference sources used by non-science majors when referring to complex topics; namely, students increase

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their use of scientific journals when they are shown how to use scientific journals and students also report a correlated decrease in non-peer reviewed sources (ie, radio, newspapers, TV). We seek to broaden this work by using pre- and post-topic student surveys in the course at the University of Wyoming to directly measure student comfort with science with the goal of quantifying how much of an impact one class can make on a student’s opinion of science. This work will show other higher education instructors both the methodology and results from this study of the interdisciplinary course on climate change. 4:00pm Deposit-feeder diets in the Bering Sea: implications for effects of climatic loss of sea ice-

related microalgal blooms Christopher A. North, James R. Lovvorn, Jason M. Kolts, Marjorie L. Brooks, Lee W. Cooper, Jacqueline M. Grebmeier

Climate warming in seasonally ice-covered seas is expected to reduce the extent and duration of annual sea ice. Resulting changes in sea ice-related blooms of ice algae or phytoplankton may in turn alter the timing, magnitude, or quality of organic matter inputs to the sea floor. If benthic taxa rely differently on direct consumption of settling fresh microalgae for growth and reproduction, altered blooms may lead to reorganization of deposit-feeding assemblages. To assess the potential for such changes, we examined the diets of five abundant deposit-feeders (three infaunal bivalves, a polychaete, and a brittle star) with different feeding modes over the course of the spring bloom in May–June 2007 in the north-central Bering Sea (30 to 90 m depth). Short-term data from gut contents reflected feeding modes, with the bivalves Macoma calcarea, Ennucula tenuis, and Nuculana radiata, and the brittle star Ophiura sarsi, responding more quickly to deposition of fresh algae than did the head-down polychaete Pectinaria hyperborea. Fatty acid biomarkers also indicated rapid ingestion of settling algae by the bivalves (especially Macoma) and the brittle star, while Pectinaria continued to ingest mainly bacteria. Fatty acid biomarkers did not indicate any unique dietary importance of ice algae released from melting ice. Longer-term inference from stable isotopes suggested that fresh microalgae contributed little to overall carbon assimilated by any of these species. Instead, deposit-feeders appeared to select a consistent fraction from the pool of sediment organic matter, probably microbes, microbial products, and reworked phytodetritus that form a longer-term sediment “food bank.” Redistribution of settled organic matter via scouring and accumulation by currents, as well as the multi-year life spans of macroinvertebrates, may further overwhelm effects of short-term variations in the timing, magnitude, and dispersion of blooms in the water column. More diet data are needed from mid-summer to account for any lag in assimilation of fresh microalgae at these cold temperatures. Nevertheless, our results suggest that if annual sea ice cover is reduced, increased production of phytoplankton during longer ice-free periods could replace inputs of ice-associated microalgae to the sediment food bank used by deposit-feeders. 4:15pm Spatial change in the Red-breasted/Red-naped Sapsucker hybrid zone Shawn Billerman, Matt Carling Hybrid zones offer unique opportunities to investigate the evolutionary processes that contribute to reproductive isolation between closely related taxa. Red-naped (Sphyrapicus nuchalis) and Red-breasted (S. ruber)

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Sapsuckers hybridize along a narrow contact zone that stretches from northern California to British Columbia and are excellent models for investigations of the evolution of reproductive isolation. I used mitochondrial DNA as a preliminary assessment of hybrid zone movement, and found Red-breasted Sapsucker haplotypes well east of the phenotypic hybrid zone. There is substantial evidence that the sapsucker hybrid zone is not stable, although it is unclear why the hybrid zone continues to move. Further, preliminary data from habitat models suggest that Red-breasted Sapsuckers may be habitat generalists, while Red-naped Sapsuckers are specialists. In addition to data already collected, I will 1) conduct a series of field experiments to investigate species recognition in the hybrid zone, 2) use a combination of genetic techniques to further characterize the historical and current genetic structure of the hybrid zone, and 3) refine habitat modeling approaches to predict how the sapsucker hybrid zone will change in the future. The combination of genetic, behavioral, and ecological approaches will allow for new insights into the processes important in population divergence and the evolution of reproductive isolation. 4:30pm Variability in forest fuels and weather influence the potential for crown fire in young

lodgepole pine forests Kellen N. Nelson, Daniel B. Tinker, Chad M. Hoffman, Paige E. Copenhaver, Monica G.

Turner, Bill H. Romme A quarter century after the 1988 Yellowstone fires, we explore how forest fuels vary across the post-fire landscape and how variation in temperature and moisture may influence wildfire behavior. We summarized fuel loads across 83 sites in Yellowstone National Park that burned in 1988 and varied temperature and moisture using the NEXUS fire behavior model to evaluate thresholds in torching and crowning index—two metrics related to crown fire likelihood. Surface fuel loads were 130±5.37 Mg/ha across the Yellowstone post-fire landscape with fine fuels (<0.25” diameter) strongly correlated with post-fire tree density and coarse fuels (≥0.25” diameter) related to legacy wood preceding the fire. Findings related to torching and crowning index indicate that fuel loads in young forests are sufficient to support crown fire but are dependent on forest density, high temperatures, and low fuel moisture. These factors may be important for forest managers to assess wildfire risk as more severe fire seasons are predicted for the Western United States.

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5:00 POSTER SESSION - Berry Center Lobby Poster 01 Working to conserve the world's most endangered antelope: range collapse, demography,

and movements of hirola in eastern Kenya Abdullahi H. Ali, Jacob R. Goheen, Rajan Amin The hirola (Beatragus hunteri) is arguably the world most endangered antelope whose extinction would mark the first loss of a mammalian genus since the thylacine in 1936. Ecological knowledge gaps, weak local involvement, and political turmoil on the Kenya-Somali border have hindered conservation of hirola since the 1970s. Unlike many globally endangered species, the historic range of hirola occurs entirely outside formally protected areas, and their fate hinges on an ability to understand and manage jointly for conservation and livestock production. Since 2010 and with strong local support, we have initiated a field research program to understand the reasons underlying hirola declines, and to explore management options to curtail these declines. Our work targets the importance of recently-recolonized predators and deteriorating range quality for hirola demography and movements, both of which have been identified by the Kenya Wildlife Service as critical priorities for research. We employ GPS telemetry, and mark-resight and sight-resight analyses. GPS-telemetered animals are enabling us to generate unprecedented data on the basic biology of this poorly-known species. In addition, we are analysing remotely-sensed imagery to determine the collective impacts of overgrazing, fire suppression, and elephant reductions on shrub encroachment in this region. Preliminary results suggest that hirola have declined in response to the conversion of open grassland to shrubland, perhaps triggered by the extirpation of elephants from northeastern Kenya in the 1970s. In addition natural hirola population shows a skewed age structure with more young animals during the calving season and more adults at other times of year. We therefore suspect a habitat degradation and predation are combining to suppress the recovery of contemporary populations. Poster 02 Sagebrush plant community and soil organic matter recovery in the absence of

reclamation following disturbance Otgonsuren Avirmed, Indy C. Burke, William K. Lauenroth and Megan L. Mobley Sagebrush steppe ecosystems once covered over 60 million hectares in the Western USA, which is declining. Abandoned, unreclaimed wellsites provide us an opportunity to pursue the rarely-addressed questions regarding long-term dynamics of sagebrush steppe ecosystems. In this study we ask the question: to what extent have sagebrush plant community composition and soil organic matter pools recovered after disturbance in the absence of reclamation? We studied sagebrush plant community and soil carbon dynamics in old oil and gas well sites that were abandoned 30-90 years ago, comparing sagebrush density, cover, and biomass; cover of other plant functional groups; and soil organic matter pools under and between shrubs at paired disturbed and undisturbed sites. We found that big sagebrush recovery takes over 80 years, longer than other shrub species, and sagebrush density recovery was faster than sagebrush cover or biomass recovery. In addition, we found out that the grass component of the community recovered faster than the forb component. Non-sagebrush shrub cover was higher in disturbed areas than undisturbed areas. Soil organic matter was significantly higher under than between shrubs, but did not differ between disturbance treatments, nor was there a trend in SOM over time. However,

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when we look at how small-scale heterogeneity of soil organic matter changes through time, we see distinctive recovery of heterogeneity associated with individual plants. Poster 03 Phenology of soil respiration is altered by field warming

Amanda Brennan, Elise Pendall, Yolima Carrillo, David Risk Soil CO2 efflux is sensitive to changes in climate as well as plant phenology. The objective of this study was to determine how field warming affects dynamics of soil respiration in a semi-arid grassland ecosystem. We hoped to understand how warming might influence diurnal patterns of CO2 efflux during different phenological stages over the course of a year, in vegetated and non-vegetated plots. The experimental design in place at the Prairie Heating and CO2 Enrichment (PHACE) site was utilized for this goal. Forced diffusion dynamic chambers were placed at the PHACE site and measured CO2 concentrations continuously for all of 2011. We expected that warming would interact with moisture availability to influence soil respiration throughout the year. We hypothesized that 1) warming would stimulate respiration in spring when water is less limiting with daytime efflux being more stimulated night; 2) warming would reduce summer CO2 efflux as a result of soil drying. We further hypothesized that total soil respiration would be more sensitive to soil moisture, whereas microbial respiration in the non-vegetated plots would be more sensitive to changes in soil temperature. Preliminary results suggest that peak respiration during daylight hours was extended by warming during the early growing season. Conversely, the daily peak respiration period was reduced late in the season. During winter months as well as before spring green-up and after fall senescence, respiration was enhanced by warming. These results suggest that the feedback associated with rising global temperatures will depend on the net annual effect with warm dry periods playing a more important role in reducing soil CO2 efflux. Poster 04 Raptors in decline: why energy development may not be to blame Jason D. Carlisle, Lindsey Sanders, Anna Chalfoun, Ken Gerow

Human-induced habitat alteration is one of the most universal threats to wildlife populations, and raptors (i.e., hawks, eagles, and owls) are no exception. In Wyoming and elsewhere, energy development is a prevalent cause of habitat alteration; and as the demand for domestic energy increases, development activities are likely to intensify and become more widespread. We analyzed a dataset of raptor nest use maintained by the Buffalo Field Office of the Bureau of Land Management (BLM) in conjunction with a concurrent dataset of coal-bed methane well construction to determine if energy development in the in the Powder River Basin of Wyoming was affecting nest use by raptors between 2003-2011, a period when more than 15,000 wells were constructed in the basin. We examined the patterns of nest use of four abundant species, Ferruginous Hawk, Golden Eagle, Great Horned Owl, and Red-tailed Hawk, in relation to both well proximity and density at multiple scales. Although nest use by these species is in decline across the study area, we found no strong evidence that the development of coal-bed methane as implemented in the Powder River Basin adversely affected raptor nest use over the period of 2003-2011. Our finding could support the idea that regulations and guidelines by which the BLM has overseen coal-bed methane development in the Powder River Basin have helped mitigate impacts

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caused by habitat alteration; however, given the limits of our research, we recommend initiating targeted study of alternative, potential causes of nest use decline including drought and prey availability. Poster 05 Comparison of classic with novel in situ extraction of soil amino acids from grassland soil Janet Chen, David G. Williams Characterization of organic and inorganic soil nitrogen availability is important for determining ecosystem response to global change, as nitrogen limitation is often a major constraint on ecosystem productivity. Classic methods of soil nitrogen extraction involve field collection of soil samples and disturbance of soil aggregates during processing. A novel method of soil amino acid extraction is described that allows the collection of semi-sterile soil water extracts in situ with minimal disturbance to soils. Comparison of samples collected using this novel method to samples collected in parallel using classic methods developed by Brookes et al. 1985 and Kielland 1994 revealed different detectable amino acid N pools relative to ammonium. Glutamate and arginine comprised the highest amino acid N pools from extracts collected from a semiarid grassland site using this new method of extraction. In contrast, samples collected and extracted using the classic method contained higher relative levels of serine, glycine and glutamate. The amounts of dominant amino acids relative to ammonium were significantly greater using the classic method compared to the new method. These observed higher ratios of amino acids to ammonium are likely the result of additional amino acid inputs by lysis of microorganisms which are not removed when filtering in the classic method. Disturbance associated with classic methods of soil N determination may have led to alterations in the quantity and distribution of ammonium and amino acids in extracts. Minimizing disturbance of soil aggregates when sampling nitrogen pools and selection of an appropriate filter for collecting free amino acids may be important for accurately determining nitrogen availability to plant roots and soil microbes. Poster 06 Ecology and Aesthetics: Why Perceptions of Nature Matter Christa Cooper Sumner There is no other species on Earth that has as great and far-reaching of an impact on Earth’s ecosystems than humans. Societies define nearly every aspect of nature – from land use, value, management, and division to determination of what is good, bad, ugly and beautiful. Aesthetic experiences guide responses to nature which include both positive and negative feelings and attitudes. These perceptions influence people’s behavior in numerous ways including policy, management, visitation, and appreciation. Many of America’s foundational policies at the forefront of environmental conservation are embedded with references to aesthetic enjoyment of our natural surroundings. In recent years, the Rocky Mountains have undergone dramatic changes in ecology and appearance due to the bark beetle. The proposed project survey aims at gaining a greater understanding of how these changes may be influencing visitor perceptions and what these perceptions could mean for forest management, conservation and educational endeavors. Questions to be addressed include: How do visitors perceive the dramatically and recently changed landscape (due to bark beetles) of the Rocky Mountains? Do they have differing perceptions of natural versus human impacts on the forest? Does knowledge of the bark

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beetle and forest dynamics impact their perceptions? And, do perceptions of the natural environment and human impacts change as a function of gender, race, ethnicity, and class? Poster 07 What limits horned lizard (Phrynosoma hernandesi) distribution and relative abudance in

Wyoming? Reilly R. Dibner, Daniel F. Doak Some species occur on every continent while others are restricted to geographic ranges of less than a few hectares in area. Species that are widespread across a broad geographic range are not, however, necessarily common. If they are tied to particular habitat characteristics, these species may be few in number. We classify species as specialists if they are limited along any single niche axis, but this fact does not mean that specialists are necessarily limited along all, or even many, niche dimensions. When species are specialists, disturbance events that change critical attributes of their habitats can threaten those species’ existence. To identify potential threats, we need to understand which habitat components are the most important to a species. I am exploring factors that may limit the population distribution and abundance of the greater short-horned lizard (Phrynosoma hernandesi) in Wyoming. Most species of horned lizards have wide distributions, but their actual occurrences are patchy. The one species of horned lizard in Wyoming tends to inhabit arid shrublands with some shrub cover and exposed sandy or loose soil, but it is unclear how important these factors are. Further, while horned lizards are all ant-eating specialists, some species have more specific diets than others. Some of these factors are susceptible to change with increasing development, some are relatively immutable, and the response of other factors is unknown. I will present preliminary data on potentially limiting factors from sites across Wyoming. Poster 08 How does the landscape affect effective population size and functional connectivity of

Greater Sage-Grouse leks? Beth A. Fitzpatrick, Melanie A. Murphy

A current need in ecology is to better understand how land conversion influences effective population size and connectivity between breeding sites. This is particularly important for declining species. Greater Sage-Grouse (Centrocercus urophasianus), a species warranted but precluded under the Endangered Species Act of 1973, has experienced a reduction in its distribution and population decline in association with anthropogenic disturbance. Sage-grouse are closely tied to sagebrush habitat; development within this habitat is known to negatively influence lek or breeding site attendance. Our goal is to understand how disturbance influences effective population size and connectivity of leks in the Powder River and Bighorn basins. We implemented a stratified random sampling design to capture variation in development and habitat fragmentation across the study area. We propose to use genetic data to assess the effect of habitat amount, configuration, and quality on effective population size and gene flow. We collected DNA samples (i.e. shed feathers) from 80 sites and will be estimating effective population size, allele frequencies, allelic richness, excess heterozygosity and genetic distance (e.eg., Fst). I hypothesize that habitat loss, a dispersed habitat configuration, and low habitat quality will

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reduce both effective population size and connectivity. This information will provide insight into how the landscape influences lek quality as well as connectivity between lek sites. Genetic measures can serve as an early warning system for population health and can be used to predict how future land development may influence population persistence. Poster 09 Seasonal and altitudinal variation in lipid, sugar and glycogen reserves in native bees Susma Giri, Michael E. Dillon The accumulation of energy reserves is critical to the survival and fitness of insects. Insects rely primarily on lipids and glycogen to fuel metabolism. Although the relative allocation of and variation in lipid, sugar or glycogen reserves have been well described for many vertebrates, very few studies have measured variation in energy reserves of insects, except in the context of diapause. Accumulation of energy reserves during the foraging season prior to diapause will strongly impact emergence and subsequent fitness. We measured allocation of energy reserves in a widespread, common native bee, Lasioglossum spp., collected from two sites (2241 and 3151 m asl) throughout the growing season (June-August) to test for seasonal and altitudinal variation in the contribution of each energy component (lipids, sugar, and glycogen). Overall, sugar was the dominant energy source, regardless of season and altitude. The relative contributions of lipids and glycogen did not vary with altitude or season. However, bees collected from high altitude had relatively more sugar in late summer. Poster 10 Can paleoecology be used to identify a Native American role in the maintenance of

longleaf pine savanna? Rachel Jones, Stephen T. Jackson

Longleaf pine savanna covered much of the southeastern United States that Hernando DeSoto passed through in the mid-16th century. Longleaf pine savanna requires a high-frequency, low-severity fire regime occurring every 2-7 years. In the absence of such fires, longleaf pine forest today is quickly replaced by oak forest. Today, less than 2% of the estimated original 37 million ha remains across the coastal plain. Although lightning is an important ignition source for surface fires in the region today, forest managers have found that the frequency and areal extent is inadequate to maintain longleaf pine savanna. Some southern ecologists have speculated that in addition to lightning caused fires, Native American fire-setting helped to maintain these savannas before European arrival. If Native American fire-setting was important in maintaining the savanna at a regional scale, and these populations declined rapidly in the mid-late 16th Century due to European disease and invasion, paleoecological records should reflect a landscape change during the 17th and 18th Centuries. Preliminary paleoecological data from Silver Lake in northwestern Florida will be shown at the symposium.

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Poster 11 The distribution of invasive species in the Falkland Islands Mikey Tabak, Sally Poncet, Ken Passfield, Carlos Martinez del Rio

Norway rats (Rattus norvegicus) have been introduced to several islands in the Falkland Archipelago and are associated negative effects on native bird species. Managers have attempted to eradicate rats from islands, but rats have recolonized some islands following eradications. We searched for a threshold distance between islands across which rats are unlikely to swim. We analyzed the distribution of rats throughout the archipelago based on several island characteristics. We found that the probability of rat presence on an island is predicted by three factors: island area, distance to the nearest rat-infested island, and the nearest large landmass (East or West Falkland). Rats are more likely to be found on islands in the west half of the archipelago, where the probability of rat occupancy increases faster with island area, compared to islands in the east half of the archipelago. At either location, and at any island size, rats are unlikely to swim a distance of greater than 3000 m.